Consultants hired by Pinellas and Hillsborough counties now estimate it would cost about $15 million to make the former Gandy Bridge safe for pedestrian traffic. That's half the preliminary estimate issued late last year.

Any repair would likely last 10 years, at which point the bridge likely would still need to be demolished.

The initial estimate was based on a three-hour boat tour under the bridge. Since then, engineers have dug into the concrete support system to get a more thorough picture of the bridge's condition.

It revealed multiple places across the span where concrete support beams are cracking, as well as undergirding steel tendons that are rusting and splitting.

With governments on both side of the bay facing sharp budget cuts, any price tag is going to get a skeptical hearing.

"Ideally, we'd preserve this trail," said Pinellas County Commissioner Nancy Bostock, who heard a presentation about the analysis Tuesday as a member of the Friendship Trail Bridge Oversight Committee. "We're looking at scaling back a lot of things right now."

Hillsborough County Commissioner Al Higginbotham, also on the committee but absent from Tuesday's meeting because of a prior commitment, said he needs to hear more.

The report estimates it would cost about $13 million to demolish the bridge, plus another $6.5 million to build two fishing piers on both sides of the bay. Higginbotham said he wants to hear community input, but also wants to know if demolition must take place soon or can be delayed without endangering boaters who travel beneath it.

"The demolition price seems high," Higginbotham said.

The engineering report offers several options:

• Spend $15 million on conventional repair techniques and a carbon fiber to strengthen the span. The cost of actual repair is $7 million, but the consultants say another $4 million would be needed for ongoing repairs in the next decade plus $4 million for contingencies.

• Repair both ends of the bridge, include catwalks used for fishing, for about $10 million. About $2 million would go to repairing the lower spans, while $6 million would go toward demolishing the raised middle.

• Demolish the entire structure for $13 million and build two new, smaller fishing piers at either end at a cost of about $4.5 million. The new fishing piers may have to be demolished when a new Gandy Bridge is built in several years.

• Demolish the entire span and build two fishing piers when a new Gandy bridge is built at a cost of $19.5 million.

Both county governments had been set to split the cost of $4.2 million in repairs beginning in November 2008. Then a final inspection turned up trouble. Steel tendons that support the span were eroding quickly, cracking in some places and sending shards of concrete into the bay

Commissioners will take up the discussion later this summer.

Bill Varian can be reached at varian@sptimes.com or (813) 226-3387.

On the Web

To see the full report by Kisinger Campo & Associates and SDR Engineering Consultants, go to www.hillsboroughcounty.org/public works. Click the "publications" link.

Trail Bridge report

To see the full report by Kisinger Campo & Associates and SDR Engineering Consultants, go to hillsboroughcounty.org/publicworks. Click the "publications" link.